Growing radicchio – varieties, sowing and caring for the lettuce

The following selection introduces you to varieties that were bred specifically for the Central European climate and have proven themselves in private kitchen gardens.

• Rosso di Chioggia – Probably the most popular radicchio variety outside of Italy, thanks to its robust constitution and excellent adaptation to our climatic conditions. The burgundy leaves are streaked with white veins. The firm heads stay crisp in the fridge for several weeks after harvest. Suitable for summer and autumn sowing
• Palla Rossa – The premium variety scores with firm, purple heads and white ribs. The lettuce is surrounded by green leaves, as with most radicchio varieties. Only in autumn does the late variety take on its conspicuous colouration, when the nights are getting colder. Suitable for summer and autumn sowing.
• Red from Verona – Very robust, compact, medium-late variety. The dark red, heart-shaped leaves enrich every summer salad with color and a unique nut aroma. Suitable for summer sowing
• Rossa di Trevisio – Historical radicchio variety from the 16th century. The heads of lettuce form long, pointed, red-green leaves. One of the most frost-tolerant varieties of all, with the potential to overwinter in beds. Suitable for sowing from April to August
• Variegata di Castelfranco – Fantastically beautiful radicchio with light green to cream-colored heads of lettuce speckled with red. The hybrid owes its nickname orchid salad to its graceful habit. The loose arrangement is reminiscent of a lettuce with strong leaves. Furthermore, the variety impresses with an unusually mild aroma, without the typical bitter aftertaste. The minimum temperature is 0 degrees Celsius. Suitable for sowing from mid-June to mid-August
• Indigo – Old-established variety with a dark red head surrounded by green leaves. This radicchio is characterized by rapid and vigorous growth. Indigo is also insensitive to the dreaded bolting and does not develop brown leaf edges. Suitable for summer sowing
• Variegata Precoce Romea – A picturesque eye catcher with red and white leaves and white ribs. The variety inspires with a harmoniously rounded taste without the typical bitter aroma dominating. In addition, this radicchio only needs a short growth phase of 6-8 weeks. Suitable for sowing from June to August
• Variegata Precoce di Luisa – The variety boasts leaves that look like they are painted. The light green and white base color is covered with crimson spots. After a short culture period of 70 days, you can harvest handy heads of lettuce weighing around 250 grams. The sweetish taste even tempts lettuce-resistant children to grab them. Suitable for sowing from June to August

sowing

To grow radicchio from seeds, you have the choice between the preculture behind glass and direct sowing in the bed. Early plants start the season with a vital growth advantage, resulting in an earlier harvest. It is important to pay attention to various aspects so that bolting does not occur later in the bed. Although direct sowing results in a later harvest, it is associated with fewer imponderables. We explain all the important details below:

preculture

The window for sowing behind glass opens in April. It is an advantage if you choose small peat pots as seed containers. Since radicchio already develops a deep taproot as a young plant, pricking out and repotting is extremely tricky. Peat pots can later be planted out with the seedling, leaving the root undisturbed. Otherwise, planting out is required after 4 weeks at the latest. Sowing is successful under the following conditions:

• Soak the seeds in chamomile tea or water for 6 hours
• Sow thinly on nutrient-poor substrate
• Just press the light germs or sieve a maximum of 0.5 cm with sand or vermiculite
• Moisten with a fine shower or pour from below

For germination is a constant temperature between 16 and 20 degrees Celsius. If there are fluctuations above or below these values, the plant in the bed tends to bolt. Therefore, place the seed pots in a heated indoor greenhouse to better control the heat. Keep the substrate constantly slightly moist and ventilate the mini greenhouse for a few minutes every day. The young radicchio are planted out from mid-May at a distance of 30 x 30 cm.

direct sowing

The selected variety defines the exact point in time for direct sowing. Wait at least until mid-May so that the temperature does not fall below the lower limit of 16 degrees Celsius.

• Plant a finely crumbly seedbed in a sunny location in humus-loose, deep garden soil
• Sow the seeds at a distance of 25 x 25 or 30 x 30 cm
• Sieve very thinly with sand, press down a little and shower over

To protect against voracious pests, pecking birds and the elements, put a transparent hood or foil tunnel over the seedbed.

Pflege des Salats

The choice of location and a balanced water and nutrient balance have a significant influence on a rich harvest of magnificent heads of lettuce. All relevant criteria are explained in more detail below.

Location
Radicchio favors a sunny, warm and sheltered location. Choose an air-flushed location so that the leaves dry quickly after a downpour and prevent rot in warm, humid weather. The Mediterranean salad makes modest demands on the soil. Normal, fresh to moderately dry garden soil usually meets the requirements. Ideally humus, loose and deep enough for the long taproot.

Watering
Whenever the soil has dried 1-2 cm deep, water your radicchio moderately. A short finger test gives more detailed information about the actual water requirement. Put the water directly on the root disk. Avoid overhead irrigation of the plant.

Fertilizing
Among the useful plants in the garden, radicchio is one of the medium feeders. You can cover the moderate nutrient requirement with organic fertilizer. 60 to 80 grams of horn meal or 3 liters of compost per square meter are best suited. Do not expose the lettuce to the concentrated nutrient load of a mineral fertilizer. On the one hand, this is how chemical ingredients get into your food; on the other hand, lettuce chicory reacts to over-fertilization with rotting heads.

hibernate

In mild locations, special winter varieties, such as Rossa de Treviso, thrive in the bed well into December and provide the kitchen with crisp, fresh salad. Protection made of fleece, straw or twigs keeps frost and permanent wetness at bay. A foil tunnel that creates a suitable microclimate is well suited, provided it is ventilated regularly.

diseases and pests

You will rarely have to complain about diseases and pests on radicchio. Properly cared for in the appropriate location, the lettuce plant proves to be largely resistant. However, salad chicory is not immune to the following health problems:

Wreath rot
It is a physiological disorder based on neglect in care. Brown spots develop on the leaves, which brown into a wreath. As time goes on, the entire leaf turns brown and dies. Fatally, this disease manifests itself in autumn on well-developed heads. The main cause is excessive nitrogen fertilization, whereupon calcium is fixed in the soil and can no longer be absorbed. Therefore avoid the administration of complete mineral fertilizers and only administer organic materials such as compost and horn shavings.

Aphids
The ubiquitous aphids in the garden do not spare radicchio. If the tiny, black, brown, white or green pests spread on the leaves, a home remedy for combating them in the early stages has proven to be excellent. In 1 liter of water add 1 tablespoon each of pure soft soap and alcohol. Placed in a spray bottle, treat the infested plant on the tops and undersides of the leaves until the lice are gone. In order to correctly assess the control success, also pay attention to ants. These are crazy about the honeydew that aphids excrete as a waste product. As long as ants are cavorting around a lettuce chicory, there are still aphids left.

Voles
The fleshy taproots of radicchio are a coveted delicacy for voles. If the rodents don’t stand up to them, they won’t stop at leaves and whole heads of lettuce. In order to prevent this damage, the young plants in endangered beds are placed in a spacious vole basket in the ground. This is a close-meshed wire netting that is first sunk into the ground before salad chicory is planted or sown.

frequently asked Questions

Which mixed culture is recommended for radicchio?
The Mediterranean salad thrives in the company of beans, cucumbers, cabbage, spinach, leeks, peas, tomatoes, chives or onions. Associated with marigolds, pests stay at a distance. On the other hand, avoid eating in the immediate vicinity of parsley, celery, endives and radishes.

Why are my radicchio heads rotting in the middle of the season?
There are primarily three triggers that are responsible for rotting radicchio lettuce heads. If warm, humid weather lasts for a long time, the leaves do not have enough time to dry. Therefore, preferably choose an air-flushed location. In addition, the lettuce is considered a medium eater. The plant reacts to an overdose of fertilizer with rot. Last but not least, waterlogging is responsible for this damage. Water only when the soil surface has dried.